check engine light

hey guys any help here would be greatly appreciated ...my check engine light came on ,and i reset it with my obd 2 reader ,but the light comes right back on .my reader shows me a code PO452 and says EVAP EMISSION CONTROL SYS PRESS SENSOR LOW .... is this something i need to return to the dealer (because it is emissions related ) or can i do it myself .... i dont have shop manuals yet ,but would rather fix it myself ..... thanks in advance pat